1. Field
The disclosed embodiments are directed to a sealed feedthrough equipped with a penetration module destined for a severe environment cell wall feedthrough of the type of those used in the nuclear or chemical industry. The disclosed embodiments likewise provide a penetration module destined for a wall sealed feedthrough. Lastly, it concerns a process of replacement of a penetration module by another module within a sealed wall feedthrough.
2. Brief Description
The disclosed embodiments find a particular application for the distribution of electric currents making possible the functioning of apparatus operating inside these cells.
The use of sealed tubular feedthroughs equipped with adapters making it possible to feed fluids or to make electrical connections inside glove boxes, or so-called “hot” cells, that is to say, inside fenced areas containing dangerous products or sources of radiations, is known in the area of nuclear installations.
Because of severe environmental conditions to which are subjected operating equipment located inside cells as well as adapters located in the wall feedthroughs of these cells, the operatives of these cells must regularly replace the adapters, which equip the said feedthroughs.
An embodiment of a sealed feedthrough is disclosed in the French patent application FR 2 698 494 A1 in which the said feedthrough extends across the wall of a cell from the hot side, namely, the interior of the fenced area which is subject to radiations to the cold side, namely the outside the said cell.
This feedthrough has the form of a sealed part of the wall constituting a cylindrical assembly sleeve into which is inserted an adapter in the form of a connector with sealed joints on the periphery of its housing, which accordingly participate in the seal of the cell. The connector is held in place inside the assembly sleeve by the travel of a locking fork actuated from the outside of the sleeve which acts in concert with a peripheral groove cut into the connector housing. In this way, the connector is fixed, whilst the fork acts in concert with the annular groove and is able to transfer travel, when the fork is extracted from the groove.
According to this embodiment, in the prior art the replacement of a connector by another connector entailed a risk of loss of seal of the wall feedthrough mainly in the gap close beside the annular groove of the housings which receives the connections of the locking fork, a drawback which this embodiment overcomes by positioning a cylindrical sleeve equipped on its periphery with sealed joints between the connector to be replaced and the replacement connector.
Although this method makes it possible to replace adapters without impairing the seal of the cell, it nevertheless necessitates the operations of extraction and insertion of the locking forks, which, in their turn, necessitate the use of precise remote-control manipulators operating likewise on the hot side of the feedthrough. Similarly, the use of an intermediate sleeve arranged between the connectors during the operation of replacement involves an additional “hot” component, which calls for a remotely controlled intervention to extract it from the hot cell and which accordingly increases the number of irradiated components to be stocked.
There is accordingly a need for simplifying the operations of replacement of adapters for wall feedthroughs by means of limiting the number of components to be manipulated by the use of remote-control manipulators, or of robotised devices inside these cells, ensuring complete preservation of the seal of the feedthrough.
This simplification of operations is mainly intended for the positioning and the introduction of new adaptors, which, as appears from patent FR 2 697 687 A1 for example, necessitates a delicate manipulation operation of the said adapters.
U.S. Pat. No. 4,666,228 describes a glove box wall feedthrough equipped with a connector comprising on its outer surface two grooves, which serve as receptacles with two sealed silicone joints acting in concert with the internal surface of the feedthrough sleeve. These two joints are positioned in the longitudinal direction of the connector body in such a way that the seal of the feedthrough is provided by at least one of the joints during the replacement by the thrust of the connector to be eliminated. The teaching of this patent is supplemented by a publication of Pave Technology Inc in which, apart from the principle of tightness, an elastic anti-withdrawal ring is mentioned and shown in accompanying figures. This publication teaches that the use of an elastic split ring to prevent the untimely withdrawal of a connector via the cold side of the glove box, is known.
Nevertheless, this ring only performs a connector anti-withdrawal function, when the connector is finally positioned in the sleeve.
Likewise, in order to ensure the full preservation of the seal of the feedthrough, there is a major need to eliminate any risk of untimely withdrawal of an adapter in service and more particularly on its introduction during the replacement operation.